François Le Loc'h

Institute of Research for Development | IRD · 195 - Marine Environmental Sciences Laboratory (LEMAR)

Species of the family Sternoptychidae (hatchetfishes) occur worldwide and play critical roles by sequestering carbon, recycling nutrients, and acting as a key trophic link between epipelagic primary consumers and higher trophic levels in marine ecosystems. Nevertheless, basic knowledge on their ecology is still lacking and their functional ecology...

In many developing countries, small-scale fisheries provide employment and important food security for local populations. To support resource management, the description of the spatiotemporal extent of fisheries is necessary, but often poorly understood due to the diffuse nature of effort, operated from numerous small wooden vessels. Here, in Gabon...

Species Distribution Models (SDMs) are useful tools to project potential future species distributions under climate change scenarios. Despite the ability to run SDMs in recent and reliable tools, there are some misuses and proxies that are widely practiced and rarely addressed together, particularly when dealing with marine species. In this paper,...

Microplastic (MP) pollution is increasing worldwide and affecting aquatic fauna in different ways, which endangers current aquatic resources in a still unknown extent. MP-induced threats to marine fauna are critical for developing countries, where waste treatment may be not optimal and coastal communities rely heavily on marine resources for dietar...

The structure of a fish food-web was described for the first time in a coastal lagoon in the southern Mediterranean Sea by analysing stable carbon and nitrogen isotopes of fish species and their potential food sources. The El Mellah Lagoon (EML) located in extreme north-eastern Algeria, is the only coastal lagoon in the southern Mediterranean with...

In the early 2010s, the French government officially launched its energy transition strategy dedicated to offshore renewable energy. Since 2011, the government has launched several calls for tender for the construction of commercial fixed offshore wind farms in the English Channel and off the Atlantic coast. In parallel, in the mid-2010s, the Frenc...

The connection between epipelagic and deep-sea mesopelagic realms controls a variety of ecosystem processes including oceanic carbon storage and the provision of harvestable fish stocks. So far, these two layers have been mostly addressed in isolation and the ways they connect remain poorly understood. Furthermore, both systems are affected by clim...

Coastal ecosystems are subjected to an increasing number of anthropogenic drivers, including marine renewable energies and climate change (CC). These drivers can interact in complex ways, which may lead to cumulative effects (CEs) whose potential consequences on the ecosystems need to be addressed. We used a holistic approach—ecological network ana...

Introduction Competition embodies species struggle for space and food and is, therefore, a critical evolutionary mechanism influencing species spatiotemporal patterns and persistence. One of the main drivers of competition is resource availability. In marine ecosystems, resource availability is determined, among other things, by habitat structural...

In the Southeastern Tropical Atlantic, Haemulidae family play an important role both environmentally, acting as a link between lower and higher trophic levels, and socioeconomically, being widely caught by artisanal fleets. This study aimed to describe the trophic ecology of three grunt species (Haemulon aurolineatum, H. plumierii and H. squamipinn...

Chemical contaminant concentrations in wild organisms are used to assess environmental status under the European Marine Strategy Framework Directive. However, this approach is challenged by the complex intra- and inter-species variability, and the different regional features. In this study, concentrations in trace elements (As, Cd, Hg and Pb), poly...

The Northeast Atlantic, a highly productive maritime area, has been exposed to a wide range of direct human pressures, such as fishing, shipping, coastal development, pollution, and non-indigenous species (NIS) introductions, in addition to anthropogenically-driven global climate change. Nonetheless, this regional sea supports a high diversity of s...

In spite of the ecological services provided by elasmobranchs, their diversity and populations are significantly declining even before appropriate assessments are conducted. This paper presents information on elasmobranch diversity in the Saudi waters of the Arabian Gulf based on fishery-independent and dependent surveys. A total of 369 individual...

The Eastern Corsican Coast (ECC) is distinguished by its shallow sandy shelf, extensive Posidonia seagrass meadows, and the relatively limited exploitation of fish in this region. To understand ECC trophic functioning and the effects of fishing in this region of the Mediterranean Sea, we applied the Ecopath and EcoTroph approaches. Our model encomp...

A trophic web is a network of complex interactions and energy links between species. These interactions can be simplified into trophodynamic models, such as Ecopath (EP) and EcoTroph (ET), important tools providing the holistic view needed for the ecosystem approach to fisheries. We describe food web structure and trophic interactions by developing...

This study aims to characterize and compare the feeding ecology of the European eels ( Anguilla anguilla L.) during the continental phase (i.e. yellow and silver) along a salinity gradient (i.e. lower, middle and upper) in six northern France estuaries (i.e. brackish water). The diet and stable isotopic (i.e. δ ¹⁵ N and δ ¹³ C values) compositions...

The lack of knowledge about highly anthropised tropical ecosystems poses a problem for their conservation. Using carbon and nitrogen stable isotopes, we studied the food web structure of the estuarine ecotone of the Santa Cruz Channel (SCC), which constitutes a critical habitat for many socio-economically important species in northeast Brazil. Ther...

The shorthead drum Larimus breviceps has an important role in the subsistence of local communities. However, studies addressing the trophic ecology of this species are still scarce. Here we present further information on the trophic ecology and ecomorphology of L. breviceps, including dietary analyses, carbon and nitrogen stable isotopes compositio...

This study provides length‐weight relationships (LWR) that had not yet been reported for four fish species belonging to four different families: Chrysichthys johnelsi Daget, 1959, Cynoglossus senegalensis (Kaup, 1858), Citharichthys stampflii (Steindachner, 1894) and Pseudotolithus typus, Bleeker, 1863. Data were collected in the Fatala estuary, re...

Integrative and spatialized tools for studying the effects of a wide variety of ecosystem drivers are needed to implement ecosystem-based management and marine spatial planning. We developed a tool for analyzing the direct and indirect effects of anthropic activities on the structure and functioning of coastal and marine ecosystems. Using innovativ...

Tropical fisheries tend to be multispecies and require management approaches adapted to high diversity but scarce and poorly informative data. Productivity and Susceptibility Analysis-PSA is particularly useful where catch or biological data are incomplete, aggregated across species or insufficient for quantitative stock assessment. We applied PSA...

The consequences of climate change for marine organisms are now well-known, and include metabolism and behavior modification, distribution area shifts and changes in the community. In the Bay of Biscay, the potential environmental niches of subtropical non-indigenous species (NIS) are projected to expand as a response to sea temperature rise by the...

The lesser African threadfin Galeoides decadactylus (family Polynemidae) is one of the most captured marine fish species in Central Africa. This study examines aspects of the reproductive biology of G. decadactylus in the Libreville area of Gabon. Fish caught with encircling gillnets and bottom gillnets were collected from May 2017 to May 2018 from...

Lanternfishes (Myctophidae) are among the most abundant, widespread, and diverse fish groups in the world ocean. They account for a significant part of oceanic fish biomass and play crucial roles in various ecosystem processes, including carbon sequestration and nutrient recycling. However, despite the increasing risks they face (e.g. global warmin...

The objective of this study was to analyse the feeding habits and trophic interactions between four oceanic predatory fish around the Fernando de Noronha Archipelago (FNA), Brazil, in the western equatorial Atlantic (3.86°S/32.42°W), internationally recognised as an environment of high economic and ecological value. For this purpose, biological sam...

Seagrass beds are increasingly impacted by human activities in coastal areas, particularly in tropical regions. The objective of this research program was to study seagrass beds characteristics under various environmental conditions in the French Antilles (FA, Caribbean Sea). A total of 61 parameters, from plant physiology to seagrass ecosystem, we...

In this poster we detail the use of ecological indicators (ENA indices) to study cumulative effects on the ecosystem functioning and on an emerging property: ecological resilience. This was made by modeling the food web of the extended Bay of Seine in the English Channel using Ecospace and by combining multiple approaches to simulate the potential...

relations taille-poids chez 20 espèces de poissons de l'estuaire du Sine Saloum au Sénégal, en afrique de l'Ouest. Les relations tailles-poids (rTP) ont été estimées pour 20 espè-ces de poisson collectées au cours des missions de pêches scientifi-ques effectuées d'avril 1990 à octobre 2012 dans l'estuaire du Sine Saloum, Sénégal, avec comme engin d...

Length‐weight relationships (W = aLb) were estimated for 5 fish species, the pearl stingray Fontitrygon margaritella (Compagno & Roberts, 1984), the West African spadefish Chaetodipterus lippei (Steindachner, 1895), the East Atlantic African spadefish Ephippus goreensis (Cuvier, 1831), the law croaker Pseudotolithus senegallus (Cuvier, 1830) and th...

To understand patterns of genetic and morphological variability, population structure and dispersal dynamics of the invasive bivalve Pinctada imbricata radiata (Leach, 1814) in Tunisian waters, we studied 200 individuals from five different sites (natural, polluted and/or subjected to environmental and anthropogenic pressures) using 10 enzymatic sy...

Jacks are highly prized tropical marine fish. Most of them complete their whole life cycle at sea but some use estuaries at the juvenile stage before moving back to coastal waters and joining the adult exploited stocks. Little is known about jacks’ trophic ecology in estuaries, although their juveniles' ability to successfully exploit available res...

Global shrimp catches are reported primarily in association with large industrial trawling, but they also occur through small-scale fishing, which plays a substantial role in traditional communities. We developed an Ecopath model in north-eastern Brazil, and applied a temporally dynamic model (Ecosim) to evaluate the potential effects of different...

relations taille-poids chez 19 espèces de poissons de deux réservoirs artificiels tropicaux (Manantali et Selingue) au Mali, en afrique de l'Ouest. Les relations longueur-poids (rLP) ont été estimées pour 19 espèces de poissons échantillonnées dans deux lacs artificiels (Manantali et Sélingué) au Mali : Brycinus leuciscus, B. macrolepi-dotus, B. nu...

We used complementary stable isotope (SIA) and stomach content (SCA) analyses to investigate feeding relationships among species of the nektobenthic communities and the potential ecological effects of the bottom trawling of a coastal ecosystem in northeastern Brazil. Carbon (δ13C) and nitrogen (δ15N) compositions were determined for five basal sour...

Estuaries are highly important nursery habitats for a range of fish species because they provide refuge and food, especially for juveniles. However, the importance of specific salinity zones and adjacent shallow marine habitats (subtidal and surf zones) for fish feeding is not well understood, particularly in small macrotidal estuaries. Using the e...

Coastal habitats are interlinked by ecological connectivity, defined as the exchange of organic matter or organisms between habitats. The degree of this connectivity will depend in particular on the geometric properties of the landscape. The increasing anthropogenic alterations in estuaries therefore raises the need to understand how their morpholo...

Spiny lobsters (Panulirus longipes, P. penicillatus and P. versicolor) are an important resource in Seychelles, where they inhabit coastal carbonate and granite reefs that have been impacted by multiple coral bleaching events over the past two decades. Little is known about their biology and ecology in this region. Interspecific competition for foo...

Mesopelagic fishes are numerically the most important vertebrate group of all world’s oceans. While these species are increasingly threatened by anthropogenic activities, basic biological knowledge is still lacking. For instance, major uncertainties remain on the behaviour, ecology, and thus functional roles of mesopelagic micronektivores, particul...

In an increasingly anthropogenic world, the scientific community and managers have to take interactions between the drivers of ecosystems into consideration. Tools like ecological network analysis (ENA) indices offer the opportunity to study those interactions at the ecosystem level. However, ENA indices have never been used to test the incidence o...

Size-based approaches are paramount tools for the study of marine food webs. Here, we investigated the relationship between zooplankton body size, stable isotope composition and trophic level (TL) along a large-scale onshore-offshore gradient in the western tropical Atlantic. Samples were obtained on the Brazilian continental shelf, slope and in oc...

Under climate change, future species assemblages will be driven by the movements and poleward shift of local species and the arrival of more thermophilic species from lower latitudes. To evaluate the impacts of climate change on marine communities in the Bay of Biscay, we used the hierarchical filters modelling approach. Models integrated 3 vertica...

There is a growing interest in the development of offshore wind farms to provide a sustainable source of renewable energy and contribute to the reduction of carbon emissions. In parallel, there is a need to better understand the effects of these installations on coastal marine ecosystems and identify potential sea use conflicts, especially when the...

The stable carbon (δ13C) and nitrogen (δ15N) isotope values of soft tissues of micronekton (crustaceans, squid, mesopelagic fish) and zooplankton were measured from organisms collected on the RV Antea at two seamounts located in the south-western Indian Ocean: La Pérouse (summit depth ~60 m) and “MAD-Ridge” (thus named in this study; summit depth ~...

This study provides information about the feeding habits, population aspects and spatial distribution of the spot­ted goatfish, Pseudupeneus maculatus, along the coast of the tropical Brazilian continental shelf. Distribution patterns are described using length frequencies and catch rates. Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N),...

Purpose The present study assesses environmental performance of seafood production by demersal trawling in Tunisia (Gulf of Gabes) in order to analyze the contribution of each production stage to environmental impacts and to understand drivers of the impacts using life cycle assessment (LCA). Then a set of ecosystem quality indicators were determin...

Environmental impact assessment (EIA) studies for offshore wind farm projects endeavour to consider the sensitivity of ecological compartments (benthos, fish, birds and marine mammals) to potential pressures/changes occurring in the ecosystem structure and functioning. EIA is expected to be conducted considering an integrated ecosystem approach, wh...

Case study for Western (Brazil) and Eastern (Cape Verde, Senegal) tropical Atlantic countries, information on marine and coastal natural resources and their use and exploitation status

Les études d’impact environnemental menées en amont des projets éoliens offshores considèrent chaque compartiment de manière individuelle, et non pas l’écosystème dans son ensemble. La compréhension des liens trophiques et l’appréhension de l’écosystème de manière holistique est pourtant un enjeu important rapporté par les politiques publiques tell...

Mayotte Island is located in Comoros archipelago and shelters multispecific meadow where nine seagrass species inhabit and which are frequented by their grazers the green turtle (Chelonia mydas) and more rarely by the dugong (Dugong dugon). With the increase of demography and coastal activities, the conservation of this threatened lagoon habitat an...

We investigated the trophic niches and the resource partitioning of two snook species, the common (Centropomus undecimalis) and the fat snook (C. parallelus), in four tropical estuaries of the northeastern Brazil, using stable isotope analyses of carbon (δ13C) and nitrogen (δ15N). Fish specimens, mainly juveniles, basal resources and a primary cons...

Ecological guilds have been widely applied for understanding the structure and functioning of aquatic ecosystems. This study describes the composition and the spatio-temporal changes in the structure of the fish fauna and the movements between the estuary and the coast of a tropical estuary, the Itapissuma/Itamaracá Complex (IIC) in northeastern Br...

Article en page 8 de la newsletter. La mutualisation des actions nationales « herbiers » de l’Ifrecor et de la DCE a conduit au lancement d’une phase de recherche et développement afin de développer des protocoles et des indicateurs sur les herbiers répondant aux objectifs de ces deux programmes. C’est dans ce cadre que la thèse intitulée « Dévelo...

Article en page 24 de la newsletter. La mutualisation des actions de l'Ifrecor et de la DCE a conduit au lancement d’une phase de recherche et développement afin de développer des protocoles et des indicateurs « herbiers ». C’est dans ce cadre que la thèse intitulée « Développement d’outils méthodologiques pour le suivi et l’évaluation de l’état d...

While breeding, seabirds are central-place foragers requiring resources to sustain high-energy requirements. Therefore, during this period, they are particularly sensitive to food-resource availability, which can vary within and between years. Intra- and inter-annual variations in Scopoli’s shearwater (Calonectris diomedea) trophic ecology were inv...

Using the Bay of Biscay (BoB) as a case study, we conducted a transnational assessment of the mean trophic level (MTL, Ospar FW4) indicator at sub-regional level, over the last three decades. Our results confirm the apparent recovery of BoB’s bentho-demersal system,as shown by trends in the MTL indicator based on survey data. However, they also poi...

In order to assist fisheries managers, ecological indicators are needed to evaluate the effects of fishing activities on marine ecosystems and to improve communication of these effects in both public and scientific contexts. Finding appropriate indicators is challenging given the complexity of marine food webs as well as the ecosystem response to f...

Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analy...

A combination of modelling tools was applied to simulate the impacts of the future Courseulles-sur-mer offshore wind farm (OWF) construction (Bay of Seine, English Channel) on the ecosystem structure and functioning. To do so, food-web models of the ecosystem under three scenarios were constructed to investigate the effect caused by the OWF of adde...

PurposeThe present study aims to understand the influence of rearing practices and the contributions of production phases of fish farming to their environmental impacts and determine which practices and technical characteristics can best improve the farms’ environmental performance. Another objective is to identify the influence of variability in f...